Stable, concentrated and dilute, oil-in-water emulsions, their processes of preparation, and formulation process employing these emulsions

Abstract

A stable oil-in-water emulsion, a process for the preparing such emulsion, and a formulation process employing the emulsion. The stable oil-in-water emulsion is obtained from an air-in-water preemulsion to which a simple or complex fatty substance is added by moderate mixing, preferably without exerting a shear force. The air-in-water preemulsion includes a surfactant, preferably a nonionic surfactant, a co surfactant chosen from hydrophilic compounds, preferably having at least one hydroxyl group, which are chosen in particular from the family of the polyols, and an aqueous phase. The ratios of these three components of the preemulsion are chosen within the region of ordered liquid crystal structure of the phase diagram of these three components and/or in ratios chosen so that the structure of the mixture of these three components, observed under a microscope in polarized light, exhibits birefringence characteristics.

1 . A stable oil-in-water emulsion, comprising:
 an air-in-water preemulsion consisting essentially in a mixture with air of three components which are a nonionic surfactant with an HLB of greater than or equal to 13, a hydrophilic cosurfactant, and an aqueous phase, the components being present in ratios that provide one of (i) an ordered liquid crystal structure according to a phase diagram of the three component mixture and (ii) birefringence under an optical microscope in polarized light for the three component mixture; and   a simple or complex fatty substance being selected from the group consisting of fatty acid esters, waxes, butters, wax esters, natural, synthetic or mineral oils, hydrogenated oils and mixtures thereof, wherein,   the stable oil-in-water emulsion is a gel obtained by mixing the air-in-water preemulsion with the simple or complex fatty substance, the oil-in-water emulsion exhibiting gustatory, pharmaceutical, dermatological or cosmetic property or function,
 the gustatory property or function being selected from the group consisting of a taste, a flavoring, a feeling in the mouth, an enrichment in vitamins, an enrichment in fatty acids, 
 the pharmaceutical property or function being a pharmaceutical activity, 
 the dermatological or cosmetic property or function being selected from the group consisting of combating aging, healing, limiting secretion of seborrhea, cleaning, protecting against UV radiation, moisturizing, emmollience, astringency, sunscreen, antiwrinkle, anti-inflammatory, anti-redness, refining and cell regeneration. 
   
   
   
       2 . The stable oil-in-water emulsion according to  claim 1 , wherein the air-in-water preemulsion is a white paste, the constituent air globules of which being observed in polarized light, their surfaces exhibiting birefringence characteristics. 
   
   
       3 . The stable oil-in-water emulsion according to  claim 1 , wherein the ratios of air-in-water preemulsion are, per 100 parts by weight of water, from 300 to 50 parts of the nonionic surfactant, and from 300 to 50 parts of the hydrophilic cosurfactant. 
   
   
       4 . The stable oil-in-water emulsion according to  claim 3 , wherein the ratios of air-in-water preemulsion comprises, per 100 parts by weight of water, from 200 to 120 parts of nonionic surfactant and from 180 to 100 parts of hydrophilic cosurfactant. 
   
   
       5 . The stable oil-in-water emulsion according to  claim 1 , wherein the nonionic surfactant is selected from the group consisting of polyglycerol fatty acid esters, which are optionally ethoxylated, and alcohol ethoxylates. 
   
   
       6 . The stable oil-in-water emulsion according to  claim 5 , wherein the nonionic surfactant is a decaglycerol fatty acid ester with an HLB of greater than or equal to 13, selected from the group consisting of decaglyceryl laurate, decaglyceryl myristate, decaglyceryl stearate, decaglyceryl isostearate or decaglyceryl oleate, and mixtures thereof. 
   
   
       7 . The stable oil-in-water emulsion according to  claim 1 , wherein the hydrophilic cosurfactant is a polyol. 
   
   
       8 . The stable oil-in-water emulsion according to  claim 7 , wherein the hydrophilic cosurfactant is diglycerol. 
   
   
       9 . The stable oil-in-water emulsion according to  claim 1 , wherein said emulsions comprises oil particles or droplets presenting a mean diameter of less than 10 μm approximately. 
   
   
       10 . The stable oil-in-water emulsion according to  claim 1 , wherein said emulsion further comprises at least one fat-soluble active agent or at least one water-soluble active agent. 
   
   
       11 . The stable oil-in-water emulsion according to  claim 10 , wherein the water-soluble active agents, which are present in the aqueous phase, are at most approximately 80% by weight of the total weight of the emulsion, and the fat-soluble active agents, which are present in the oily phase, are at most approximately 92% by weight of the total weight of the emulsion. 
   
   
       12 . A process for adding or improving a gustatory, pharmaceutical, dermatological or cosmetic property or function of an emulsion comprising the steps of:
 a) choosing a first individual emulsion to which a gustatory, pharmaceutical, dermatological or cosmetic property or function is to be added or to be improved,   b) choosing a stable oil-in-water emulsion according to  claim 1  exhibiting the gustatory, pharmaceutical, dermatological or cosmetic property or function to be added to the first emulsion or to be improved in the first emulsion.   c) mixing the stable oil-in-water emulsion, which has optionally been diluted beforehand, with the first individual emulsion to be improved; and   d) optionally diluting the mixture with an aqueous phase.